Nighttime Basal Dosing Device

ABSTRACT

A basal hub for attaching to an infusion base is disclosed. The hub includes a fluid reservoir and pressure actuating device. A septum portion of the reservoir is configured to be opened by a flow cannula that is in fluid communication with an infusion cannula of the infusion base, when the basal hub is attached to the infusion base. The pressure actuating device applies pressure to the fluid reservoir, such that when the septum portion of the fluid reservoir is pierced by the by the flow cannula, liquid stored in the fluid reservoir is released from the fluid reservoir into the infusion cannula of the infusion base via the flow cannula. The basal hub is configured to deliver a basal dose of insulin during periods of inactivity, such as during sleep time.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a division of U.S. patent application Ser. No.13/370,274, filed on Feb. 9, 2012, which is incorporated by reference inits entirety. This application also claims the benefit under 35 U.S.C.§119(e) of U.S. Provisional Application Nos. 61/441,278, filed on Feb.9, 2011, and 61/447,636, filed on Feb. 28, 2011, the disclosures of bothof said applications also being incorporated herein by reference intheir entirety.

FIELD OF THE INVENTION

The present invention relates to components and elements of infusionsystems, and more specifically to an infusion system that can be usedfor basal delivery of insulin or other liquid medicament during periodsof rest without the need for permanent attachment of a separate tubesetand pump device.

BACKGROUND OF THE INVENTION

A large number of people with diabetes use some form of daily insulintherapy to maintain close control of their glucose levels. Currently,there are two principal modes of daily insulin therapy. The first modeincludes syringes and insulin pens. These devices are simple to use andare relatively low in cost, but they require a needle stick at eachinjection, typically three to four times per day. The second modeincludes infusion pump therapy, which entails the use of an insulinpump. Although the initial cost of the pump can be significant, theoverwhelming majority of patients who have used pumps prefer to remainwith pumps. This is because infusion pumps, although more complex thansyringes and pens, offer the advantages of continuous infusion ofinsulin, precision dosing, and programmable delivery schedules. Thisresults in closer blood glucose control, which can result in improvedhealth outcomes for the patients.

The use of an infusion pump requires the use of a disposable component,typically referred to as an infusion set, line set, extension set orpump set, which conveys the insulin from a reservoir within the pumpinto the skin of the user. An infusion set typically consists of a pumpconnector, a length of tubing, and a hub or base from which an infusioncannula (i.e., an infusion needle or a flexible catheter) extends. Thehub or base has an adhesive which retains the base on the skin surfaceduring use, which may be applied to the skin manually or with the aid ofa manual or automatic insertion device.

However, there are problems associated with the delivery of insulin bysuch devices during sleep. During sleep, people tend to move and suchmovement can result in accidental disconnection of the line set, removalof the infusion cannula, or tugging of the line set that can result intunneling or leakage at the infusion site. Tunneling can occur when aninfusion cannula that has been inserted into a user leaks insulin alongthe outer walls of the tubing of the infusion cannula, back to the skin,usually after a large bolus. Since many components are attached to theuser of such devices, this further adds to the level of discomfort tothe user, reducing the comfort level of the user during periods of restwhen discomfort should be minimized.

In addition, during periods of rest, such as during sleep at night, adiabetic patient is subject to different conditions than during times ofactivity, such as during the day. During sleep time, since the patientdoes not eat, the level of insulin required (basal dose) is nearlyconstant and substantially reduced as compared to the insulinrequirement (bolus dose) at meal times or during active times during theday.

Accordingly, a need exists for a device that can deliver basal dosemedication to the subcutaneous or intradermal skin layer, during timesof rest, while maintaining a high degree of comfort to the user byeliminating unnecessary components that contribute to user discomfort.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a relatively smallbasal delivery system that is not connected to a tubeset or pump when itis used during times of rest or when the patient is disconnected fromthe infusion pump for extended periods.

Another object of the present invention is to provide a pressurizedfluid reservoir having a septum that allows release of fluid when theseptum is opened.

Another object of the present invention is to provide a spring actuateddevice or mechanical element to apply pressure on the fluid reservoir.

Another object of the present invention is to provide an elastic orflexible membrane attached to the cover of the device to form thepressurized fluid reservoir.

Another object of the present invention is to provide a flow cannulathat is secured on an infusion hub connector or adapter that isconfigured to open the integral septum.

These and other objects are substantially achieved by providing a basalhub configured to attach to an infusion base. The basal hub includes acover, a fluid reservoir within the cover, and a septum connected to thefluid reservoir. The septum is configured to be opened by a flow cannulaof the infusion base, and the flow cannula is in fluid communicationwith an infusion cannula of the infusion base. The septum is positionedon the fluid reservoir, and a pressure actuating device applies pressureto the fluid reservoir, such that when the septum of the basal hub isopened by the flow cannula, liquid stored in the fluid reservoir isreleased from the fluid reservoir into the infusion cannula of theinfusion base via the flow cannula and into the infusion cannula. Thebasal hub maintains a high degree of comfort to the user by allowing theuser to receive basal therapy without being connected to an infusionpump.

BRIEF DESCRIPTION OF THE DRAWINGS

The various objects, advantages and novel features of exemplaryembodiments of the present invention will be more readily appreciatedfrom the following detailed description when read in conjunction withthe appended drawings, in which:

FIG. 1 is a plan view of an exemplary infusion set in which an exemplaryline set is attached to an exemplary infusion base;

FIG. 2 is a plan view of the device of FIG. 1 after the line set hasbeen disconnected and removed from the infusion base;

FIG. 3 is a plan view of an exemplary basal hub of the present inventionbeing aligned for attachment to the infusion base of FIG. 2;

FIG. 4 is a plan view of the basal hub of FIG. 3 attached to theinfusion base of FIG. 3;

FIG. 5A includes a plan view and a side view of the basal hub of FIG. 3shown attached to the infusion base of FIG. 2;

FIG. 5B is a cross-sectional view of the line set device of FIG. 2attached to the infusion base of FIG. 2;

FIG. 6A is a cross-sectional view of the exemplary basal hub device ofFIG. 3 in accordance with an embodiment of the present invention;

FIG. 6B is a cross-sectional view of an exemplary infusion base with aflow cannula that is aligned to penetrate a septum of the device of FIG.6A, the infusion base being adapted to receive the exemplary device ofFIG. 6A;

FIG. 7A is cross-sectional view of another exemplary basal hub device inaccordance with another embodiment of the present invention;

FIG. 7B is a cross-sectional view of another exemplary infusion basewith a flow cannula that is aligned to penetrate a septum of the basalhub device of FIG. 7A, the infusion base being adapted to receive thebasal hub device of FIG. 7A;

FIG. 8A is cross-sectional view of another exemplary basal hub device inaccordance with another embodiment of the present invention;

FIG. 8B is a cross-sectional view of another exemplary infusion basewith a flow cannula that is aligned to penetrate a septum of the basalhub device of FIG. 8A, the infusion base being adapted to receive thebasal hub device of FIG. 8A;

FIG. 9A is side view of another exemplary infusion base; and

FIG. 9B is a cross-sectional view of the infusion base of FIG. 9A.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

The exemplary embodiments of the present invention described belowprovide a novel means for basal delivery of insulin or other medicamentto the subcutaneous or intradermal layer of skin while the user is notconnected to a standard insulin pump or other reservoir.

An exemplary embodiment of the present invention includes a basal hubthat is similar in size and shape to a sterile or sanitary hub that iscommonly attached to an infusion base when the line set or extension setis disconnected from the infusion base, to protect the infusion basethat is attached to a diabetic patient from contamination.

The basal hub generally incorporates a flexible reservoir that ispreloaded by a spring or other mechanical element or device that appliespressure to the flexible reservoir. Also included is a septum in thereservoir positioned to engage with a flow cannula located in orprovided on the infusion base, such that when the basal hub is attachedto the infusion base and the flow cannula pierces the septum, insulinfrom the reservoir will flow into the infusion site. The flow cannulaand spring are sized and configured to provide a specific flow rate thatcorresponds with the diabetic patient's nighttime basal requirement,reflecting the diabetic patient's weight, metabolism and other factors.The size of the reservoir can be varied for customized use, within thelimits of the size of the basal hub.

Currently marketed infusion sets (not shown) may include a sanitaryhub/protective hub that covers the connection site on the infusion baseduring brief periods when the line set or extension set is disconnected.For instance, when the patient is about to swim or take a shower, theline set is preferably disconnected from the infusion base, and aprotective or sanitary hub is placed on the infusion base, in lieu ofthe line set, in order to protect the fluid interface fromcontamination.

As illustrated in FIGS. 1-4, the infusion set 20 and the basal hub 30are similar in size to a conventional infusion set and its sanitary hub,respectively. However, unlike the conventional protective hub, the basalhub 30 also incorporates a reservoir or pressurized bladder 34 that caninfuse insulin at a preset basal rate during periods of inactivityincluding sleep, without being connected to a separate line set or pump.

Prior to sleeping, the basal hub 30 attaches to the infusion base 10, ina manner similar to that of the extension set 20 or line set, after theextension set 20 has been removed from the infusion base 10. Incontrast, in a conventional infusion set, the tube set remains connectedto its pump (not shown) while the diabetic patient sleeps, so that thepatient receives his/her nighttime basal dose from the pump. However,the presence of the pump and tube set creates complications for thediabetic patient while sleeping, since, as the patient moves duringsleep, line set tugging or unintended disconnection can occur.

During sleep, since only basal dosing is required, as opposed to a bolusdose before a meal, for a diabetic patient, a small hub, similar in sizeto a protective hub or sanitary hub that can be attached and detached ina manner similar to a line set, is provided and configured with apre-loaded flexible reservoir or bladder 34, illustrated in FIG. 6A,containing a quantity of insulin that is released at a predeterminedrate during sleep without the need to connect the basal hub 30 to a tubeset during use, that in turn connects to a pump containing insulin. Theabsence of an external tube set and additional components, such as apump, provides clear advantages over conventional infusion sets when thediabetic patient is sleeping or resting for a period of time.

FIG. 1 illustrates a line set 20 attached to the infusion base 10 (asshown in FIG. 2). An infusion cannula 15, illustrated in FIG. 5, isattached to the infusion base 10. The infusion cannula 15 penetrates theskin of the diabetic patient during use, with initial penetration beingfacilitated by a separate introducer needle (not shown) as is known inthe art. A rigid metal needle may be used in place of the infusioncannula 15, in which case a separate introducer needle is not required.Thereafter, the adhesive pad 18, attached to the infusion base 10,adheres to the skin of the patient to secure the infusion base 10 andthe infusion cannula 15 on the patient's skin. The housing or hub 22 ofthe extension set 20 is connected to a tube set 24, which is thenconnected to a pump (not shown) containing a reservoir of insulin orother liquid medication.

FIG. 2 illustrates detachment of the extension set 20 from the infusionbase 10. The infusion base 10 includes a flow cannula 16 at an uppersurface thereof. The flow cannula 16 and the infusion cannula 15 areshown in greater detail in FIGS. 5B and 6B.

FIGS. 3 and 4 illustrate the attachment of the inventive basal hub 30 onthe infusion base 10 after removal of the extension set 20. The basalhub 30 may have a marking 31, such as a color spot, for better visualidentification, or a see-through cover to reveal the internalcomponents. FIG. 5A further illustrates the attachment of the basal hub30 to the infusion base 10.

FIG. 5B illustrates a cross-sectional view of the line set 20 attachedto infusion base 10. The infusion base 10 includes a main base portion12, an infusion cannula 15 extending through the main base portion 12,and an infusion hub connector or adapter 14 having a flow cannula 16. Asillustrated in FIG. 5B, the flow cannula 16 and adapter 14 can be madeas a single unit. A fluid path is formed from the opening 162 of theflow cannula 16 to the distal opening 151 of the infusion cannula 15. Anadhesive pad 18 is attached to an outer surface of the main base portion12 and is also attached to the skin of the diabetic patient.

The line set 20 functions to deliver insulin into the flow cannula 16 ofthe infusion base 10. As illustrated in FIG. 5B, the line set 20includes a housing or hub 22, tube set 24 attached to the hub 22 at thehub port 26, and septum 29. The tube set 24 is connected to a pump (notshown) that delivers insulin into the tube set 24. A fluid path 28exists between the tube set 24 and the septum 29. The septum 29 isclosed when the line set 20 is detached from the infusion base 10. Theseptum 29 is positioned on the hub 22 such that when the line set 20 isattached to the infusion base 10, as illustrated in FIG. 5B, the flowcannula 16 of the infusion base 10 pierces the septum 29. After theseptum 29 is pierced by the flow cannula 16, insulin flows from the pump(not shown) into the tube set 24, through the flow path 28, into theflow cannula 16 via its open tip 162, and into the infusion cannula 15to deliver insulin into the patient through the distal opening 151 ofthe infusion cannula 15. This is the preferred way to deliver insulinwhen the diabetic patient is active and requiring different levels ofinsulin, such as at meal times (requiring a bolus dose) or during activetimes of the day. However, during sleep time, since the patient isinactive and does not intake any food, the required level of insulin(basal dose) is greatly reduced and relatively constant in comparison tothe insulin requirements during the day or during active times.

The basal hub 30 illustrated in FIG. 6A can replace the line set 20during sleep time of the diabetic patient. The basal hub 30 is aself-contained unit that is not connected to an external device, such asthe tube set 24 and external pump, for receiving and transferringinsulin to the patient, unlike the line set 20.

Before sleeping, the patient disconnects the line set 20 from theinfusion base 10. When the line set 20 is detached from the infusionbase 10, the flow cannula 16 is withdrawn from the septum 29 of the lineset 20 and the septum 29 self-closes the opening pierced by the flowcannula 16, to prevent pathogens or foreign matter entering the fluidpath 28 of the line set 20. After the line set 20 has been removed frominfusion base 10, the infusion base 10 can receive a basal hub 30.

As illustrated in FIG. 6A, the basal hub 30 includes an outer cover orhousing 32 that is relatively rigid, in order to protect the structureswithin the basal hub 30. The basal hub 30 includes a pre-loadedcompression spring 36 that pressurizes a sealed, flexible reservoir orbladder 34. The spring 36 encircles a cylindrical post 56 and the spring36 is compressed between the housing 32 and a plate 58 that is part ofthe post 56. The spring 36 presses on the plate 58 and pressurizes thebladder 34 which is positioned between the plate 58 and a septum 38 anda lower portion 39 of the housing 32. The lower portion 39 of thehousing 32 can be a separate piece that is assembled with the rest ofthe housing 32 and then attached together. The septum 38 can be madeintegral with the bladder 34. With reference to FIG. 6A, the cylindricalpost 56 can be a splined shaft, with mating spline features of thesplined shaft molded to the cover or housing 32. The cylindrical post 56is slideable on the mating spline features of the housing 32, with thespring 36 tensioned between the cover 32 and the plate 58 of thecylindrical post 56. This arrangement provides proper alignment of thecylindrical post 56 with the cover or housing 32, and also providesalignment for the spring 36 as the pressurized bladder 34 releases itscontents.

When the basal hub 30 illustrated in FIG. 6A is connected to theinfusion base 10 illustrated in FIG. 6B, the flow cannula 16 of theadapter 14 pierces the septum 38 of the basal hub 30, upon which eventthe spring force of the spring 36 and the inner diameter and length offlow cannula 16 determines the basal infusion rate through the infusioncannula 15, as insulin from the bladder 36 enters flow cannula 16through its open tip 162 and exits through the distal opening 151 of theinfusion cannula 15. Both the infusion rate of insulin and the reservoirvolume, as well as the diameter and length of the flow cannula, arepreset to the specific requirements of the diabetic patient, accordingto the patient's weight, metabolism and other factors. The basal hub 30can be prefilled with insulin in a variety of different configurationswith different combinations of insulin capacity and flow rate to suitdifferent users. Guide element 322 can be cylindrical and incorporatedinto the housing 32 to act as a guide, such that the adapter 14 of theinfusion base 10 is positioned inside the cylindrical guide element 322to align the flow cannula 16 to properly penetrate the septum 38.

The reservoir 34 may be flexible but it can also be non-flexible, as ina cylinder and piston arrangement, in which case the spring 36 orsimilar mechanical element acts on the reservoir as a piston to releasethe insulin via the septum 38 that has been opened or pierced by theflow cannula 16 when the basal hub 30 is attached to the infusion base10.

As illustrated in FIG. 6B, there is fluid communication between the flowcannula 16 and the infusion cannula 15. Once the flow cannula 16 piercesthe septum 38 that is integral with the bladder 34, upon attachment ofthe basal hub 30 to the infusion base 10, a fluid path is created fromthe reservoir 34, through the flow cannula 16, and to the infusioncannula 15, so that insulin in the reservoir is delivered to the patientat the desired basal rate.

FIG. 7A illustrates another basal hub embodiment of the presentinvention. Basal hub 30′ of FIG. 7A provides the intended function ofthe basal hub 30 of FIG. 6A with a fewer number of components and isgenerally more basic or rugged in design. The basal hub 30′ of FIG. 7Ahas been simplified to include three basic components, namely asubstantially rigid cover 110, a flexible and resilient membrane 120with a septum 125 that can be molded into the flexible and resilientmembrane 120, and a retention or retaining ring 130. The fluid reservoir140 is formed between the cover 110 and the flexible membrane 120, asillustrated in FIG. 7A.

The flexible membrane 120 is stretched over the domed surface 115 of thecover 110 and is retained in place by the retaining ring 130, with theretaining ring 130 capturing a bead 122 of the flexible membrane 120, asillustrated in FIG. 7A, to contain the fluid reservoir 140. As the fluidreservoir 140 is filled under pressure with insulin or other medication,the flexible membrane 140 stretches away from the cover, as illustratedin FIG. 7A to accommodate the insulin or other medication. The insulincan be filled in the fluid reservoir 140 through the septum 125 orthrough an opening (not shown) in the cover 110 that is closed after theinsulin has filled the fluid reservoir 140. The tension of the flexiblemembrane 120 provides the infusion pressure, as illustrated in FIG. 7A,in place of a spring 36 or similar mechanical element. The retainingring 130 can be directly attached to the cover 110 by adhesive,ultrasonic welding or other joining methods. The basal hub 30′ of FIG.7A can be attached to the infusion base 10′ of FIG. 7B in a mannersimilar to the attachment of the basal hub 30 of FIG. 6A on the infusionbase 10 of FIG. 6. Guide elements can be provided on the basal hub 30′and/or the infusion base 10′ to properly align the elements so that uponattachment of the basal hub 30′ to the infusion base 10′, the flowcannula 16′ penetrates the septum 125 so that insulin in the fluidreservoir 140 flows into the flow cannula 16′ via the open tip 162′ andinto the infusion cannula 15 to administer the insulin to the diabeticpatient. The rate of flow of the insulin from the fluid reservoir 140can be determined by several factors, including the tension force of theflexible membrane 140, the diameter of the open tip 162′ of the flowcannula, the diameter of the distal opening 151, the lengths of the flowcannula 16′ and infusion cannula 15,and so on.

The infusion base 10′ of FIG. 7B is similar to the infusion base 10 ofFIG. 6B, but the cannula 16′ is not part of the adapter 14′. The cannula16′ includes a flanged base 163 that positions and rests the cannula 16′on the adapter 14′, as illustrated in FIG. 7B. One or more elements ofthe infusion base 10, 10′, including the flow cannula 16, 16′, adapter14, 14′, infusion cannula 15, and the main base portion 12 can be madetogether (e.g. by injection molding) or separately and assembled to formthe infusion base 10, 10′. In still another embodiment, utilizing asteel cannula, the flow cannula and the infusion cannula could becombined into a single element, with or without an adapter to secure theelement to the main base. The flanged feature or flanged base 163 at theinfusion cannula 16′ can be replaced with a bulged portion in thecombined single element, which can be produced in a forming processsimilar to the process used to form the head on a capacitor pin.

As illustrated in FIG. 7A, the domed surface 115 of the cover 110includes an indent 117 which allows the cannula 16′ to draw fluid fromthe fluid reservoir 140, as the fluid reservoir 140 becomes depletion.Upon attachment of the basal hub 30′ to the infusion base 10′, the flowcannula 16′ penetrates close to the indent 117, and as the tension ofthe resilient membrane 120 is released, the resilient membrane 120 isdrawn toward the domed surface 115 of the cover 110, and the remainingamount of the fluid in the fluid reservoir 140 is directed to the indent117 to be drawn into the flow cannula 16′. The embodiment of FIGS. 8Aand 8B illustrate similar use of an indent.

FIG. 8A illustrates another exemplary basal hub 30″ that is similar tothe basal hub 30′ of FIG. 7A, but the basal hub 30″ includes an indent127 at its septum 125. FIG. 8A shows the basal hub 30″ attached to theinfusion base 10′ when the flow cannula 16′ initially penetrates theseptum 163. This is the initial state of the fluid reservoir 140′.Thereafter, the fluid reservoir 140′ becomes gradually depleted asinsulin flows from the fluid reservoir 140′ into the flow cannula 16′and exits through the infusion cannula 15.

FIG. 8B illustrates the state when the fluid reservoir 140′ is fullydepleted, with the remaining insulin being directed into the indent 127formed on the septum of the resilient membrane 120. Due to the indent127, most of the fluid in the fluid reservoir 140′ can be administeredto the diabetic patient.

FIGS. 9A and 9B illustrate another exemplary infusion set 10″ designedto better accommodate the introducer needle (not shown) that typicallyextends into the infusion cannula 15 to permit insertion of theintroducer needle and infusion cannula 15 into the patient, withoutinserting the introducer needle into the flow cannula 16″. Typically,the introducer needle is removed and a septum (not shown) closes theexit point of the introducer needle in the infusion base 10″. In FIGS.9A and 9B, however, an alternative design is shown in which the flowcannula 16″ is included in the infusion base 10″ and is displacedlaterally away from the site of the introducer needle. A fluid path isformed through the adapter 14″ from the open tip 162″ of the flowcannula 16″ to the distal tip 151 of the infusion cannula 15 after theintroducer needle has been removed from the infusion base 10″.

The basal hub 30, 30′, 30″ can be modified for use with the infusion set10″ by repositioning the septum 38, 125 to be opened by the flow cannula16″ when the basal hub 30, 30′, 30″ is attached on the infusion base 10″of FIGS. 9A and 9B. Alternatively, as is the case in the precedingembodiment, the introducer needle can pass through both the flow cannulaand the infusion cannula.

The basal hub 30, 30′, 30″ is intended to be used in conjunction withthe line set 20 of FIG. 5B. The basal hub 30, 30′, 30″ can also bemodified or adapted for use with commercially available line sets.

Since the line set 20 and pump (not shown) is disconnected before theusage of the basal hub 30, 30′, 30″, this can result in a loss ofinsulin infusion data for the patient. At present, insulin infusionpumps generally capture the infusion profile of the entire 24-hour day,and this record can be downloaded to a patient's health care providerfor analysis.

Although the pump controller can be modified to allow the user to enteror record his/her total nighttime basal requirement, another embodimentof the present invention allows the infusion profile to be capturedduring sleep. This can be done by making the basal hub 30, 30′, 30″ anintegral part of the infusion set. In this embodiment, in preparationfor sleeping, the patient disconnects the hub 22 of the line set 20 fromthe infusion base 10, implements a command from the infusion pumpcontroller to fill the device reservoir 34, 140, 140′ with the quantityof insulin required for the nighttime basal dose, disconnects the lineset 20, and connects the basal hub 30, 30′, 30″ to the infusion base 10,10′ 10″. With this process, the total nighttime insulin dose is recordedas a bolus dose by the infusion pump without requiring any modificationto the pump controller.

The reservoir 34, 140, 140′ is designed to stop the outflow of itsliquid contents when disconnected from the infusion base 10, as theseptum 38, 125 self-closes after the flow cannula 16, 16′, 16″ iswithdrawn from the septum 38, 125. Reconnection of the basal hub 30,30′, 30″ to the infusion base 10, 10′, 10″ results in insulin flow fromthe reservoir 34, 140, 140′ to the infusion site.

The infusion base 10, 10′ 10″ and basal hub 30, 30′, 30″can be designedto retain a pressurized volume of insulin that is sufficient for thepatient to utilize during sleep of approximately 8 hours. The pressureelement in the infusion set 10, 10′, 10″ (e.g. a compression spring 36)can be preloaded or charged using the pressure of the infusion pump, incombination with a separate septum or check valve (not shown) in theinfusion base 10, 10′, 10″. In this case, a connection port is providedin the basal hub and the user attaches the line set hub or connector tothe connection port to redirect the insulin flow internal to the hub 22,allowing the nighttime reservoir to fill. Once the connection is made,the user implements a command from the infusion pump controller to fillthe flexible reservoir 34, 140, 140′ with the total dose for nighttimebasal delivery. The user then disconnects the line set hub or connectorfrom the hub 22. The basal hub 30 can be modified to be filled from theline set whereupon the line set is disconnected, or the infusion set hubcan be modified to incorporate a basal reservoir which is filled usingthe pump at nighttime before the line set is disconnected.

The line set hub of a conventional infusion set can also be redesignedto incorporate the basal reservoir 34, 140, 140′ to retain a pressurizedvolume of insulin that is sufficient for the patient to utilize duringsleep of approximately 8 hours. The pressure element in the infusion set10, 10′, 10″ (e.g. a compression spring 36) can be preloaded or chargedusing the pressure of the infusion pump, in combination with atwo-position valve (not shown) in the line set hub. In this case, theuser shifts the two-position valve to redirect the insulin flow internalto the line set hub, allowing the nighttime reservoir to fill. Once thevalve is shifted, the user implements a command from the infusion pumpcontroller to fill the flexible reservoir 34, 140, 140′ with the totaldose for nighttime basal delivery. The user then disconnects the lineset 20 from the hub 22 and shifts the two-position valve back to theoriginal setting. The flow of insulin from the basal reservoir 34, 140,140′ passes through a reduced orifice to the infusion cannula 15 so thatthe basal infusion is restricted and maintained at a predetermined rate.

The use of a flexible reservoir or bladder 34, a compression spring 36preloaded to exert a force on the bladder 34, and a flow cannula 16 witha specified diameter and length, can provide a predetermined andrelatively constant flow rate of insulin or other medication to bereleased from the basal hub 30. Similarly, for the basal hub 30′, 30″,the amount of pressure in the fluid reservoir 140, 140′ can be regulatedby the tension on the flexible membrane 120.

The flow cannula 16, 16′, 16″, as well as the infusion cannula 15, canbe a one-piece injection molded unit formed of a polymer, or it can bemade of steel or other metallic material. Upon connection of the basalhub 30, 30′, 30″ to an infusion base 10, 10′, 10″, an end of the flowcannula 16, 16′, 16″ penetrates the septum 38, 125 of the basal hub 30,30′, 30″. The flow cannula 16, 16′, 16″ may be sharp or blunt. However,if it is blunt, the septum 38, 125 may need to be pre-slit orpre-pierced to accommodate such a blunt cannula. Upon awakening fromsleep, the patient removes the basal hub 30, 30′, 30″ from the infusionbase 10, 10′, 10″ and connects a line set 20, as illustrated in FIG. 5B,to the infusion base 10, 10′, 10″.

When basal infusion is not provided for a diabetic patient, bloodglucose level will rise, on average, by one (1) mg/dl for each minutethat an infusion set is not connected. During sleep, a number ofproblems may occur, e.g. the infusion line or tube set may become kinkedor pinched, or the line set may disconnect from the infusion base, allof which may result in the patient's blood glucose level increasing overtime, potentially causing serious harm to the patient. Thus it isessential for the diabetic patient to reliably receive basal infusionduring rest periods or when the patient is disconnected from theinfusion pump for extended periods. The disclosed embodiments of thepresent invention meet this need.

Although only a few exemplary embodiments of the present invention havebeen described in detail above, those skilled in the art will readilyappreciate that many modifications are possible in the exemplaryembodiments without materially departing from the novel teachings andadvantages of this invention. Accordingly, all such modifications areintended to be included within the scope of this invention as defined inthe appended claims and their equivalents.

What is claimed is:
 1. A delivery system for delivering liquidmedication comprising: an infusion base for attaching an infusioncannula to a user; an extension set for attachment to the infusion baseand delivering liquid medication into the infusion cannula; and a basalhub for attachment to the infusion base after the extension set has beendisconnected from the infusion base to deliver liquid medication intothe infusion cannula.
 2. The delivery system as claimed in claim 1,wherein the basal hub comprises a fluid reservoir and a pressureactuating device that applies pressure to the fluid reservoir.
 3. Thedelivery system as claimed in claim 2, further comprising a flow cannulaattached to the infusion base; wherein when the basal hub is attached tothe infusion base, the flow cannula opens the fluid reservoir, andliquid stored in the fluid reservoir flows through the flow cannula andthe infusion cannula.
 4. The delivery system as claimed in claim 1,wherein the extension set comprises a set hub, tube set and a pump, thetube set connected to the set hub and the pump to deliver liquidmedication from the pump into the infusion cannula of the set hub. 5.The delivery system as claimed in claim 1, wherein the basal hub isconfigured to deliver a basal dose of insulin during a period of sleepor inactivity.
 6. The delivery system as claimed in claim 1, wherein thehub is sized and configured to attach to and administer a basal dose toa conventional infusion base.
 7. A method of administering liquidmedication to a patient, comprising: during a first period of time,administering liquid medication to the patient from a remote infusionpump through an extension set to an infusion base that is attached tothe patient; detaching the extension set from the infusion base; andduring a second period of time, administering liquid medication to thepatient from a reservoir in a basal hub attached to the infusion base.8. The method as claimed in claim 7, wherein during the first period oftime, liquid medication is administered by the extension set comprisinga set hub, tube set and a pump, the tube set being connected to the sethub and the pump to deliver liquid medication from the pump into theinfusion cannula of the set hub.
 9. The method as claimed in claim 7,wherein during the second period of time, liquid medication isadministered by the basal hub that delivers liquid medication from thereservoir into an infusion cannula of the set hub.
 10. The method asclaimed in claim 7, wherein the first period of time is a waking periodand the second period of time is a sleeping or resting period.
 11. Themethod as claimed in claim 7, wherein the first period of time is adaytime period and the second period of time is a nighttime period. 12.The method as claimed in claim 7, wherein the hub is configured todeliver a basal dose of liquid medication during periods of inactivity.13. The method as claimed in claim 7, further comprising the steps of:after the step of detaching the extension set from the infusion base andbefore the second period of time, implementing a command from aninfusion pump controller to fill the reservoir of the basal hub with aquantity of liquid medication required for a basal dose, and recordingthe basal dose as a bolus dose by the infusion pump.
 14. The method asclaimed in claim 7, further comprising the steps of: after the step ofdetaching the extension set from the infusion base and before the secondperiod of time, implementing a command from an infusion pump controllerto fill the reservoir of the basal hub with a quantity of liquidmedication required for a basal dose; and capturing a total dosedelivered during a period of sleep or inactivity as part of a totaldaily dose.
 15. The method as claimed in claim 7, wherein liquidmedication comprises insulin.